You're much better off with starfire with a camaral+mykens build. Those chains tend to travel! This is the build I'm running at the moment. I swap between IAS, Stun, and Damage with slow time, and swap between gogok and stricken for gems. https://us.battle.net/d3/en/profile/Blackmorgrim-1728/hero/42023928
Hydras just melt single targets, while chain deals well with packs, the slow time helps bunch up large packs enemies.
My largest Manald crits tend to reach 200,000M+ (200 Trillion?) and I can reliably complete GR 70-71.